toxoplasmosis
Table of contents:
Antigen
Hassl codicillo primo operis toxoplasmatos causa
Chromatographic and immunological investigations on antigen constituation of Toxoplasma gondii. |
An aqueous lysate of Toxoplasma gondii trophozoites was divided into fractions with molecular weights of > 10E3, 320, 65, 27, 6, and < 1 kd respectively by gel filtration. The fractions were separately collected and individually tested against human and rabbit antisera in an ELISA. The fractions proved to be of different | reactivity. The fraction with the highest reactivity (320 kd) was separated in a SDS-PAGE to analyse its protein composition. Gel filtration turned out to be a useful primary step for the separation of complex antigen mixtures and for the purification of independent components. |
Obwaller codicillo primo operis toxoplasmatos causa
An enzyme-linked immunosorbent assay with whole trophozoites of Toxoplasma gondii from serum-free tissue culture for detection of specific antibodies. |
This paper describes a new procedure of preparation of the antigen for an enzyme-linked immunosorbent assay (ELISA) for detection of antibodies against Toxoplasma gondii. To examine the reliability of this ELISA using whole trophozoites produced in a serum-free tissue culture as an antigen, 221 sera were tested comparatively in the new system (TTE, total trophozoites ELISA), in the indirect fluorescent antibody test (IFAT), and in a commercially available ELISA using sonicated trophozoites as an antigen (STE, sonicated trophozoites ELISA). The ELISA with antigen lysate showed a good correlation with the IFAT; however, false-negative results were sometimes obtained. | The TTE was performed with all sera in two modifications: one test with an anti-IgG conjugate (G-TTE) and the other with an anti-Ig-G, -M, -A conjugate (GMA-TTE). In none of these TTE modifications were insensitivities observed; however, the G-TTE seems to offer a clearer differentiation between specifically reactive and nonreactive findings. The present study shows that the ELISA with whole trophozoites produced in serum-free tissue culture might be used as an alternative test to the IFAT. This test combines the advantages of the ELISA system with the sensitivity and specificity of the IFAT. |
Circulating Antigen
Hassl codicillo primo operis toxoplasmatos causa
Experimental studies on the appearance of circulating antigen after infection with Toxoplasma gondii. |
The appearance of circulating antigen (cag) of Toxoplasma gondii was studied in experimentally infected rabbits and compared with the course of IgG and IgM titers. Cag was not detected until the 31st day and remaind detectable until the 53rd day p.i., much later than the IgM peak. The late detection of cag can be explained by the assumption | that the ELISA used in our studies reacts mainly with antigens which are released by destruction of Toxoplasma cells due to the immunological response of the infected organism. The current concept concerning the significance of the detection of cag for the early diagnosis of Toxoplasma infections in man needs critical revision. |
Hassl codicillo primo operis toxoplasmatos causa
Studies an the significance of detection of circulating antigen (cag) for the diagnosis of a primary infection with Toxoplasma gondii during pregnancy. |
In the course of a screening program for toxoplasmosis for pregnant women 121 serum samples of 87 women with serolo-gically proven fresh Toxoplasma infections were tested for circulating antigen (cag) in an ELISA. 7 sera contained cag. Simultaneously, high titres of specific antibodies were found in all these sera. Evaluation of | all serological results led to the conclusion that the infection of all women with cag had occured 2 to 4 months ago. Thus, the detection of cag in sera of pregnant women may be considerably helpful in confirming the diagnosis of an active infection as well as for determining the onset and duration of the infection. |
Antibodies
Hermentin codicillo primo operis toxoplasmatos causa
A Solid-Phase Indirect Haemadsorption Assay (SPIHA) for Detection of Immunoglobulin M Antibodies to Toxoplasma gondii: Application to Diagnosis of Acute Acquired Toxoplasmosis |
A solid-phase indirect haemadsorption assay SPIHA) for the detection of immunoglobulin M (IgM) antibodies to Toxoplasma _gondii is described. Polystyrol microtiter plates are coated with anti-human IgM (p-chain-specific) antibodies and then sequentially allowed to react with patient's serum and sheep erythrocytes sensitized with soluble antigen of Toxoplasma gondii. A total of 111 sera were tested in fluorescent antibody test (FAT and IgM-FAT), complement fixation test (CFT), indirect haemagglutination assay (IHA), and in SPIHA. 47 sera were from individuals with a suspected or verified acute Toxoplasma | infection. In most of these cases the SPIHA allowed a clear interpretation with respect to the status of the infection, even when the 1gM-FAT was not conclusive. In contrast to IgM-FAT, rheumatoid factor or exceedingly high specific IgG antibodies did not interfere with results in SPIHA. A laboratory-acquired infection enabled us to demonstrate the course of immune response measured by SPIHA as well as by IgM-FAT, FAT, CFT, and IHA. The method proposed here is well appropriated to IgM detection, simple to perform, inexpensive, and thus representing an alternative to IgM-FAT, convenient for the routine laboratory. |
Toxoplasma gondii features
Hassl codicillo primo operis toxoplasmatos causa
Isoenzyme Studies on Toxoplasma gondii Isolates Using Isoelectric Focusing. |
Zymogram analysis using isoelectric focusing on polyacrylamide gels was performed to characterize and distinguish two Toxoplasma gondii isolates (strains BK and RH). The activity of the following 14 enzymes in the cell lysates was investigated: IDH, MDH, ME, 6PG, G6P, LDH, IPO, HEX, PGM, EST, ALP, ACP, LAP, and PGI. Nine enzymes (IDH, G6P, LDH, HEX, PGM, EST, ALP, ACP, and PGI) showed distinct and reproducible | banding patterns, and four of them (IDH, G6P, EST, PGI) enabled a reliable distinction of the two Toxoplasma gondii isolates. A contamination of the parasite extracts with host proteins could be excluded by comparison of the enzyme activities of the Toxoplasma isolates with mouse peritoneal exudate cells. Isoenzyme analysis proved to be a helpful method for a characterization and a distinction of Toxoplasma gondii isolates. |
Hassl codicillo primo operis toxoplasmatos causa
New tools in the laboratory diagnosis of Toxoplasma infections. |
Within the last decades a great variety of methods for a laboratory diagnosis of Toxoplasma infections and of toxoplasmosis has been developed. Nevertheless, the situation concerning golden standards or standardised tests has not improved nor consolidated due to a multiplication of the number of test systems in use. Thus, newly developed test methods have to be judged by their suitability to improve diagnosis in problematical cases of toxoplasmosis diagnosis: Such increasing areas of unsatisfactory conditions are the diagnosis | of reactivations in immunosuppressed patients, the onepoint diagnosis of asymptomatic primary infections, and the rapid diagnosis of prenatal infections in newborns. Although techniques of parasite DNA detection, mostly PCR, have improved the diagnostic procedure especially in cases of transplacental infections and of reactivations; the use of simple, serological methods remains unsatisfactorily. Unfortunately, a significant breakthrough in the fields of poor diagnostic efficiency is not forthcoming at present. |
|